Bernoulli conveyor

ABSTRACT

An improved Bernoulli conveyor comprises an endless belt supported above and propelled along a surface by angled airjets issuing from ports which are formed in the surface and define a path for the belt. In a further improvement, a plurality of paths are so defined, the ports in each path communicating with respective manifolds which are selectively pressurized to switch the path of the belt. A similar switching technique is employed for individual documents supported above and propelled along selectable paths on a surface without a belt. Additionally, an improved port configuration is disclosed for issuing the angled jets wherein the port wall flares outwardly in the conveyor surface so as to permit the Coanda phenomenon to cause the jet to issue along the surface, thereby increasing the propelling component of the angled jet.

United States Patent [72] Inventor Richard J. Range Silver Spring, Md.

[21] Appl. No. 862,287

[22] Filed Sept. 30, 1969 [45] Patented Oct. 19, 197 1 [73] Assignee Bowles Fluidics Corporation Silver Spring, Md.

[54] BERNOULLI CONVEYOR [56] References Cited UNITED STATES PATENTS 756,600 4/1904 Dodge 302/31 3,136,539 6/1964 Lyman 271/26 Primary Examiner-Andres H. Nielsen Attorney-Rose & Edell ABSTRACT: An improved Bernoulli conveyor comprises an endless belt supported above and propelled along a surface by angled airjets issuing from ports which are formed in the surface and define a path for the belt. in a further improvement, a plurality of paths are so defined, the ports in each path communicating with respective manifolds which are selectively pressurized to switch the path of the belt. A similar switching technique is employed for individual documents supported above and propelled along selectable paths on a surface without a belt. Additionally, an improved port configuration is disclosed for issuing the angled jets wherein the port wall flares outwardly in the conveyor surface so as to permit the Coanda phenomenon to cause the jet to issue along the surface, thereby increasing the propelling component of the angled jet.

INPUT CGNTRUL PATENTED DU 1 9 l97l SHEET 2 UF 2 INVENTOR RICHARD J. RANGE ATTORN EYS BERNOULLI CONVEYOR BACKGROUND OF THE INVENTION The present invention relates to conveyors, and more particularly to improved Bernoulli conveyors of the type wherein articles are supported above and propelled along a surface by a series of angled airjets directed from the surface toward the articles The utilization of the Bernoulli effect in conveying mail and similar articles along a surface is well known in the prior art, such utilization being typified by the system disclosed in US. Pat. No. 3,317,039 to Wadey. The Wadey patent discloses a conveyor having a surface which is provided with a plurality of ports, angled in the direction of conveyancing, and arranged to issue jets of air. An article placed on the surface is impacted in turn by each jet, the velocity of which is converted to a pres sure at the impact point. This pressure applies a force against the article, one component of the force acting normal to the surface and tending to displace the article from the surface, the other force component acting in the conveyancing direction. In addition, the air from the jet is continuously escaping at a high velocity from the narrow space between the article and the surface, creating a low static pressure in this space because of the well known Bernoulli principle. When the article is very close to the surface, the low static pressure is lower than atmospheric pressure and a resulting force is applied to the article which directs it toward the surface. The further the article is away from the surface, the more closely the static pressure between the article and surface approaches atmospheric. Assuming a horizontal surface, the article achieves a vertical balance when the Bernoulli force and gravity force acting to pull the article toward the surface is balanced by the vertical component of the impact force produced by the air jets. In this vertical position the article is propelled along the surface on a shallow relatively frictionless air cushion without requiring any moving parts to drive the article.

The system described above is limited in at least three important areas. First, articles conveyed by the Wadey system can follow only one path, namely that defined by the port orientation; there is no selective path capability without introducing moving parts which are relatively unreliable and are subject to frictional wear and failure. Second, only articles having at least one large flat surface can be conveyed by a system such as Wadey's because the Bernoulli forces require such a surface in order to effectively support the article above a surface. Third, the angled jets of Wadey are directed so as to provide a substantial lifting force component to the conveyed article. It is highly desirable that the angle of jet be more acute relative to the conveyor surface in order to increase the propulsion force and decrease the lifting force. However, the smaller the angle made by the jet with the surface, the longer the nozzle through which the air must flow to issue at the surface, assuming the thickness of the conveyor baseplate remains the same. The longer the nozzle, the greater the pressure drop becomes for the airjet, and consequently the poorer the system efficiency becomes.

It is therefore an object of the present invention to provide a Bernoulli conveyor system which is capable of selectively switching conveyed articles between different paths without requiring moving parts.

It is another object of the present invention to provide a Bernoulli conveyor system capable of conveying any article, regardless of its shape, along any one or more predetermined paths.

Still another object of the present invention is to provide an improved port configuration for redirecting airjets in a Bernoulli conveyor closer to the propulsion direction.

SUMMARY OF THE INVENTION In accordance with one aspect of the present invention a Bernoulli conveyor is provided with ports for issuing angled jets arranged in plural predetermined paths. The ports in each path are supplied pressurized air from an individual manifold, the various manifolds being selectively pressurized. Each path has at least some ports sufi'iciently proximate some ports of another path so that a conveyed article overlaps ports of both paths in this region. If one of the paths is suddenly depressurized and the other pressurized, a conveyed article which had been following the one path will automatically switch to the other path. The reason for this is that a conveyed article tends to center itself over the path-defining ports so that escaping air has passages of equal length by which to escape from under the article transversely to the direction of conveyance. An article so centered on the one path is automatically recentered on the other path when the former is depressurized and the latter is pressurized. To effect selective pressurization of the manifolds without employing moving parts, fluidic amplifiers are employed. The resulting system permits selective routing among plural paths on a Bernoulli conveyor without utilizing moving parts.

In a second aspect of the present invention, the Bernoulli conveyor principle is adapted to drive an endless belt on which articles of any shape or configuration may be conveyed. The belt is supported away from and driven about a member having a continuous surface through which the angled jets are issued. Where necessary, an additional Bernoulli surface is disposed beneath the member, issuing angled jets against the belt for additional support of the belt which might otherwise tend to sag along the underside of the member and thereby frictionally engage the member at its ends. The switching technique described above for individual articles is also appropriate for the endless belt, the belt being selectively displaced transversely of its driven direction in accordance with which of the various path-defining ports are pressurized.

In still another aspect of the present invention, the angled jets are issued from specially configured noules which effect boundary layer lock-on of the issued jets to the surface from which the jets are issued. More specifically, the nozzle wall is tapered gradually away from the nozzle centerline to provide a smooth transition with the conveyor surface. The jet attaches to this wall and surface, thereby providing a greater flow component in the propulsion direction and a smaller flow component normal to the conveyor surface.

BRIEF DESCRIPTION OF THE DRAWINGS The above and still further objects, features and advantages of the present invention will become apparent upon consideration of the following detailed description of specific embodiments thereof, especially when taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a side view in section of a prior art Bernoulli conveyor, employed herein to illustrate the underlying principles of one aspect of the present invention;

FIG. 2 is a top view of the conveyor of FIG. 1;

FIG. 3 is a diagrammatic illustration of one embodiment of the present invention;

FIGS. 4 and 5 are top and side section views respectively of another conveyor embodiment of the present invention;

FIG. 6 is a top view of another conveyor embodiment of the present invention;

FIGS. 7 and 8 are top and partial side-section views respec tively of still another conveyor embodiment of the present invention;

FIG. 9 is a side view in section of the improved nozzle configuration of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Referring now to FIGS. 1 and 2 of the accompanying drawings there is illustrated a prior art Bernoulli conveyor 10 comprising a conveyor table 11 having flat, horizontally disposed top surface 13. A series of nozzles 15 are defined through table 11 and have their downstream ends arranged flush with surface 13. Nozzles 15 are arranged linearly to define a transport path extending from left to right in FIGS. 1 and 2; in addition the nozzles are angled relative to surface 13 so that fluid issuing from the downstream end of each nozzle has one flow component normal to surface 13 and one flow component parallel to surface 13 in the transport direction (lefi to right as viewed in FIGS. 1 and 2). Nozzles 15 receive pressurized fluid (for example, air) at their upstream ends by means of respective inlet ports 17 which are in turn connected to a manifold 19 by means of appropriate fluid passages and fittings.

An article to be conveyed 21, for example an envelope, is placed on surface 13. The vertical position (1) of envelope 21 above surface 13 is determined by the weight W of the envelope, the velocity of the angled airjets issuing from nozzles 15, and the angular orientation of nozzles 15 relative to surface 13. The impact of the airjets against the envelope tends to lift the envelope; on the other hand the weight W of the envelope tends to bring it closer to surface 13. In addition, the high-velocity air escaping from beneath envelope 21 creates a low static pressure region below the envelope which tends to draw the envelope toward the surface 13. Consequently a dynamic vertical force balance system is created on the envelope at some distance 1 above the table. If the envelope is raised beyond 1, the static pressure beneath the envelope decreases, tending to the draw the envelope closer to the table; if, on the other hand, the distance between the envelope and table is decreased to less than 1, the static pressure beneath the envelope increases and lifts the envelope.

In the horizontal plane, the horizontal component of the angled jets imparts a left-to-right motion (as viewed in FIGS. 1 and 2) to the envelope because of the viscous forces caused by the air flowing along the underside of the envelope. The air escapes from underneath the envelope 21 both from under the front end (the right end in the drawings) and the sides of the envelope. I have found that the air escaping from under the sides tends to keep the envelope longitudinally centered relative to the linear path defined by nozzles 15. More specifically, consider the envelope 21 to be displaced to position 21' indicated by dotted lines in FIG. 2; that is, the envelope is displaced to the left when looking in the direction of transport. In this position the escaping air from nozzles 15 is presented with a longer restrictive path in flowing from under the left side than from under the right side of the envelope; consequently the air escaping from under the left side is at a lower velocity. The viscous forces produced by the escaping air on the underside of the envelope are therefore greater in the direction transversely right than transversely left of the transport direction. This transverse force imbalance tends to displace the envelope transversely to the right of the transport direction until it is longitudinally centered over nozzles 15, in which position the transverse flow restrictions on opposite sides of nozzles 15 are equal. The envelope is thus also in a horizontal force balance system transversely of the transport direction, which force balance tends to keep the envelope longitudinally aligned with nozzles 15. I have made use of this discovery to provide a system for selectively switching a transported article between various predetermined transport paths. Such a system is illustrated in FIG. 3.

In FIG. 3 there is illustrated a conveyor table 22 having a first transport section 23 along which an article is transported (upwardly as viewed in FIG. 3) by means of airjets issuing from linearly aligned nozzles arranged longitudinally along section 23. The nozzles of section 23, and of all sections of table 22, may be similar in configuration to nozzles 15 of FIG. 1, or more preferably are configured as described in relation to FIG. 9 hereinbelow. The nozzles of section 23 are fed pressurized air from manifold 25, which in turn is selectively pressurized by an appropriate control unit 33.

From section 23 table 22 branches into three sections, namely left section 24, central section 26 an right section 28. Each of these sections includes a respective longitudinally extending path defined by nozzles terminating in the upper surface of table 22. The nozzles of lefi section 24 receives pressurized air from manifold 27; the nozzles of central section 26 receive pressurized air from manifold 29; and the nozzles of right section 28 receive pressurized air from manifold 31. Pressurized air is selectively supplied to manifolds 27, 29, and 31, one at a time, by means of control unit 33. The latter, in order to minimize the number of moving parts, may be a pair of fluidic amplifiers arranged to pressurize a specific one of these manifolds in accordance with input control conditions which may be operator initiated or automatically responsive to article reception at the ends of various sections 24, 26 and 28. The nozzles in these various sections are angled to propel articles longitudinally along their respective sections. In addition, the transport paths, determined by the linearly arranged nozzles in table sections 24, 26 and 28, must be sufficiently close together at their ends closest to table section 23 to enable article 20, upon reaching the end of section 23, to overlap at least one nozzle from all three of sections 24, 26 and 28. This latter consideration is necessitated in order that article 20 may be properly steered into whichever of sections 24, 26 or 28 has its nozzles pressurized.

In operation, an article 20 to be transported is placed on table 22 aNd traverses section 23, assuming manifold 25 is pressurized. Upon reaching the end of table section 23, the leading edge of article 20 overlaps all three first nozzles associated with the three respective table sections 24, 26, 28. If we assume that manifold 27 is pressurized and manifolds 29 and 31 are not, article 20 is steered to the left because of the phenomenon described above in relation to FIG. 2 whereby the article tends to center itself longitudinally along a path defined by the angled airjets. In addition, the horizontal component of the airjets in table section 24 is angled slightly to the left relative to the horizontal components of the jets in table section 23, and therefore the viscous forces produced by the air on article 20 also tend to steer the article to the left. In like manner, if manifolds 29 or 31 are pressurized, article 20 can be directed along table sections 26 or 28 respectively.

It is not intended to limit the inventive concepts illustrated in FIG. 3 to the specific details shown therein. For example, control unit 33 need not contain fluidic elements but rather may employ any known technique for selectively pressurizing one of three fluid passages or manifolds. Likewise, a branch from one into three table sections is not to be construed as limiting; rather, any number of input paths to a junction may feed any other number of output paths from that junction.

Referring now to FIGS. 4 and 5 there is illustrated another aspect of the present invention. More particularly, a transport table 35 has a flat horizontal top surface 37 and a flat horizontal bottom surface 39. Surfaces 37 and 39 are generally pie shaped with their converging end truncated somewhat. In addition both ends of surfaces 37 and 39 form circular arcs about a common point A located on the longitudinal centerline C/L of surfaces 37, 39 and closer to the converging end of these surfaces.

A first group of linearly aligned angled nozzles 41 terminate at surface 37 and define a first transport path extending between the ends of surface 37 and intersecting centerline C/L at point A. Nozzles 41 are each angled to impart to fluid issuing therethrough a flow component along the path defined by these noules. Pressurized air is selectively supplied to nozzle 41 from a common manifold 42. A second group of linearly aligned angled nozzles 43 tenninate at 37 and define a second transport path extending between the ends of surface 37 and intersecting both centerline C/L and the path formed by nozzles 41 at point A. The paths defined by nozzles 41 and 43 thus describe an X" having an intersection point at A. Nozzles 43 are each angled to impart to fluid issuing therethrough a flow component along the path defined by these nozzles. Pressurized air is selectively supplied to nozzle 43 from a common manifold 44.

An endless transport belt 45 is disposed about table 35 so as to encircle a portion of each of the wide convergent end and narrow divergent end of surfaces 37 and 39. The length of belt 45 is sufficient to leave a small gap between the belt and table along the entire belt length. Belt 45 is preferably made from a suitable variety of rubber or similar material to permit the belt to frictionally engage an article placed thereon for transport. The edges of table 35 between the various surfaces encircled by the belt are rounded to permit smooth transport of the belt.

Manifolds 42 and 44 receive pressurized air from respective left and right outlet passages 47 and 49 of fluidic amplifier element 50. The latter is preferably, though not necessarily, of the bistable type and includes a power nozzle 55 adapted to receive pressurized air and issue a power stream of air to either of outlet passages 47 or 49 in accordance with whichever of left and right control nozzles 51, 53 respectively last received a fluid input signal to deflect the power stream.

The unit of FIGS. 4 and 5, as described thus far, operates as follows: Assuming power stream flow through left outlet passage 47 of fluidic amplifier 50, manifold 42 becomes pressurized and angled airjets issue from nozzle 41. Regardless of the initial alignment of belt 45, it assumes the position shown by solid lines in FIG. 4 and begins travelling clockwise (as viewed in FIG. 5) about table 35. The reason for belt 45 assuming its solid-line position is explained by the same phenomenon which causes article 21 of FIG. 2 to automatically become longitudinally centered over nozzles 15. More particularly, because of the circular contour of the ends of table 35, belt 45 is rotatable with respect thereto about point A. As such the belt must overlap at least one, and in most cases two or three of nozzles 41, which, when pressurized, tend to rotate the belt into longitudinal alignment with the path defined by nozzles 41. Once so aligned, the belt continues to travel clockwise about table 35 at a speed determined by the horizontal component of the angled jets issuing from nozzles 41. If now fluidic amplifier 50 is switched to provide pressurized air to nozzles 43, belt 45, because of its overlap of one or more of nozzles 43, is rotated into alignment with the path defined by these nozzles. In this manner the belt may have its transport direction selectively switched between two (or more if desired) directions. In addition it is to be noted that the article placed on the belt for transport can have any shape and need not be limited to having a flat surface which will pennit Bernoulli action.

Depending upon the weight of articles to be transported and the mass of the belt material, the system of FIGS. 4 and 5 as thus far described is completely operable. In some cases it may be desirable to continue the paths of nozzles 41 and 43 along the underside of table 35 in order to impart additional propulsion to the belt along its entire transport path. In certain cases however the belt may be required to have so large a mass that the attracting Bernoulli forces between the belt and the underside of table 35 are insufficient to prevent the portion of belt 45 beneath table 35 from dropping substantially. This causes the belt to pull against the end surfaces of the table and creates substantial frictional impediment to belt transport. To alleviate the problem an additional member 57 having a flat horizontal upper surface 59 is placed close to and parallel with the underside of table 35. Nozzles 63 may be arranged in two linearly aligned groups corresponding to the linear group of nozzles 41 and 43; or alternatively, noules 63 may be randomly spaced on surface 59 so that various ones issue jets into impingement with belt 45 at each of the positions of the belt. Nozzles 63 receive pressurized air from a pressurized common manifold 61.

The effect of member 57 and nozzles-63 on the device of FIGS. 4 and 5 is as follows: The angled airjets issued from nozzles 63 create a Bernoulli effect between belt 45 and surface 59. This places the portion of the belt travelling beneath table 35 in a vertical force balance system, in which the belt is sup ported parallel to and between table 35 and member 57. There is no significant droop in the belt at the underside of table 35 under these conditions. Therefore the belt does not engage the ends of the table, and is transported smoothly and at high speed.

In a test of the embodiment of FIGS. 4 and 5, with a Mylar belt approximately 4 feet long and 1 foot wide, belt speeds up to two hundred fifty inches per second were measured. Switching time between belt positions took on the order of 2 to 4 seconds.

Numerous selectively attained transport paths may be laid out for operation of a device similar to that illustrated in FIGS. 4 and 5. For example, in FIG. 6, three such transport paths are illustrated, defined by three groups of linearly aligned nozzles 65, 67 and 69 respectively. These groups have the leftmost nozzle A on surface 37 in common and extend in three respective linear paths therefrom toward the diverged end of table 35. Depending upon which group of nozzles is pressurized, the belt 45 can assume any one of three positions, pivoting about nozzle A while switching. This configuration thus permits an article to be placed on belt 45 at one location and be transported to any one of three selectable locations. It is important to note that belt 45 must overlap at least one of the nozzles defining the path to which it is being switched.

Referring now to FIGS. 7 and 8 of the accompanying drawings, still another embodiment of the present invention is illustrated wherein a table 71 has flat, horizontally disposed and rectangularly configured top and bottom surfaces 73 and 75 respectively. A first group of angled and linearly aligned nozzles 77 terminates at surface 73 and defines a first transport path. Nozzles 77 are angled to impart a horizontal component from left to right (in FIG. 7) to flow through nozzles 77. Nozzles 77 receive pressurized air from manifold 79. Another group of angled nozzles 81 is disposed adjacent nozzles 77 and may also be linearly aligned, although this latter arrangement is not necessary. It is important however that the transport belt 83, when longitudinally aligned with nozzles 77, overlaps nozzles 81. Nozzles 81 are angled to impart a horizontal component to flow therethrough which is transverse to the direction of belt 81. More particularly, this horizontal component of flow from nozzles 81 is directed downward as viewed in FIG. 7. Nozzles 81 are selectively supplied pressurized air via common manifold 85.

A second transport path for belt 83 is defined by a group of linearly aligned and angled nozzles 87. The path defined by nozzles 87 is parallel to that defined by nozzles 77; but for the reasons discussed below, nozzles 87 and 77 need not be less than one width of belt 83 to permit effective switching of the belt. Nozzles 87 are angled to impart a horizontal component from left to right (in FIG. 7) to flow therethrough. Nozzles 87 receive pressurized air from selectively pressurized manifold 89. Still another group of angled nozzles 91 are arranged in the same relationship to nozzles 87 as nozzles 81 are arranged to nozzles 77. The horizontal flow component from nozzles 91 is directed (upward in FIG. 7) opposite to that from nozzles 81. Nozzles 91 receive pressurized air from selectively pressurized manifold 93.

Endless belt 83 is disposed about table 71 with suitable clearance therebetween.

In operation, assume the belt 83 to initially be in the position indicated by solid lines in FIG. 7, namely longitudinally aligned over nozzles 77. Assuming nozzles 77 to be pressurized, the belt is transported about table 71 in this position. If now it is desired to move the belt to the position indicated by dotted lines, namely longitudinally aligned over nozzles 87, manifold 79 is depressurized and manifolds and 89 are pressurized. The causes airjets to issue from nozzles 81 and 87. The jets from nozzles 87 initially have no effect on the belt; however the jets from nozzles 81 maintain the Bernoulli separation between the belt and surface 73 while moving the belt transversely across surface 73 toward nozzles 87. When the belt reaches nozzles 87 the transport motion of the belt is resumed and the belt aligns itself to be longitudinally centered over nozzles 87. In similar fashion, nozzles 91 may be employed to move belt 83 transversely toward nozzles 77.

If required, the embodiment of FIGS. 6 and 7 may also include an additional Bernoulli support of the type disclosed in FIG. 5 and including member 57. Moreover, it is now apparent that it is possible, using the technique disclosed herein, the displace an article or endless belt transversely of a transport direction by a distance which is substantially greater than the transverse width of the article or belt. To this end several rows of angled jets with transverse (to transport direction) flow components may be employed, each row in sequence acting on the belt or article to displace it toward a new desired position.

Referring now to FIG. 9 of the accompanying drawings there is illustrated a preferred nozzle configuration for use with the above-described conveyor systems of the present invention. The nozzle is formed in solid member 95, which may for example be one of the conveyor tables described hereinabove. The nozzle includes an inlet port for receiving pressurized fluid from a manifold or some other source and a constricted passaged 99 downstream of port 97 and angled through member 95 in a direction so as to provide a component to flow therethrough which is parallel to surface 98 of member 95 at which the downstream end of passage 99 terminates. At the downstream end of passage 99, the passage wall on the side toward which passage 99 is angled is cut back in a gradual taper so as to provide a smooth transition at the juncture between that portion of the passage wall and surface 98. The taper in such as to permit a stream of fluid directed through the nozzle to attach to this passage wall (by means of the well-known Coanda efiect) and remain attached to surface 98 after issuing from the nozzle. A configuration of this type reduces the flow component of the issued jet which is normal to surface 98; on the other hand, the jet component parallel to surface 98 is substantially increased over that produced by a nozzle of similar length and angle without the tapered downstream end. The degree of taper appropriate to achieve the desired boundary layer attachment of the jet to surface 98 is set forth in U.S. Pat. No. 3,396,619.

It is to be understood that whereas the above-described Bernoulli conveyor embodiments include linear-aligned angled nozzles for defining transport paths, linearly aligned nozzles are not truly necessary. Rather, the important considerations for the nozzles are:

l. The nozzles should be angled to issue fluid jets having a component in the transport direction; and

2. The relative orientation of the nozzles defining any trans port path should be such that viscous forces of the escaping fluid against the transported member are balanced in a horizontal plane, transverse to transport direction, so that the transported member can assume the desired longitudinal alignment along the path.

While I have described and illustrated one specific embodiment of my invention, it will be clear that variations of the details of construction which are specifically illustrated and described may be resorted to without departing from the true spirit and scope of the invention.

lclaim:

l. A Bernoulli conveyor for transporting objects having a relatively flat surface along selectable ones of a plurality of predetermined transport paths, said conveyor comprising:

a first member having a transport surface along which said transport paths are defined, said first member having a plurality of groups of nozzles defined therein, the downstream end of each nozzle terminating at said transport surface, the nozzles in each group being disposed relative to one another to define a respective one of said transport paths, each nozzle being angled relative to said transport surface to impart to fluid flowing through that nozzle a flow component directed along the transport path of which that nozzle defines a part, each transport path being sufficiently proximate at least one other transport path at at least one location on said transport surface to permit said relatively flat surface of one of said objects while being transported along said each transport path at said one location to overlap at least one nozzle of said at least one other transport path;

a plurality of fluid passages, one each for each of said groups of nozzles, each passage being arranged to deliver pressurized fluid applied thereto to the upstream end of all the nozzles in a respective group of noules; and

means for applying pressurized fluid to selective ones of said fluid passages;

whereby said objects are supported a short distance from and propelled along said surface of fluid jets issuing from whichever group of nozzles has pressurized fluids applied thereto, and whereby upon switching pressurized fluid from one to another of said groups of nozzles whenever an object overlaps at least one nozzle of each group said object switches from the transport path defined by said one group of nozzles to the transport path defined by said another group of nozzles;

wherein the object supported a short distance from and transported along said transport surface is an endless conveyor belt surrounding said first member.

2. The combination according to claim 1 wherein at least two of said transport paths intersect at said one location on said transport surface, said first member being contoured to permit said endless belt to be spaced said short distance from said first member when being transported along each of said transport paths.

3. The combination according to claim 2 further comprising a second member disposed beneath said first member for preventing said endless belt from sagging while passing beneath said first member, said second member including a support surface disposed proximate the underside of said first member to permit said endless belt to pass between said support surface and the underside of said first member, said second member including means for issuing pressurized fluid from said support surface against said endless belt to cause said endless belt to move parallel to said support surface while under said first member.

4. The combination according to claim 3 wherein said means for issuing includes a second plurality of nozzles terminating at said support surface and angled to impart to flow therethrough a flow component in the transport direction of said endless belt at the underside of said first member, and means for supplying pressurized fluid to said second plurality of nozzles.

5. A Bernoulli conveyor for transporting objects having a relatively flat surface along selectable ones of a plurality of predetermined transport paths, said conveyor comprising:

a first member having a transport surface along which said transport paths are defined, said first member having a plurality of groups of nozzles defined therein, the downstream end of each nozzle terminating at said transport surface, the nozzles in each group being disposed relative to one another to define a respective one of said transport paths, each nozzle being angled relative to said transport surface to impart to fluid flowing through that nozzle a flow component directed along the transport path of which that nozzle defines a part, each transport path being sufficiently proximate at least one other transport path at at least one location on said transport surface to permit said relatively flat surface of one of said objects while being transported along said each transport path at said one location to overlap at least one nozzle of said at least one other transport path;

a plurality of fluid passages, one each for each of said groups of nozzles, each passage being arranged to deliver pressurized fluid applied thereto to the upstream end of all the nozzles in a respective group of nozzles; and

means for applying pressurized fluid to selective ones of said fluid passages;

whereby said objects are supported a short distance from and propelled along said surface by fluid jets issuing from whichever group of nozzles has pressurized fluid applied thereto, and whereby upon switching pressurized fluid from one to another of said groups of nozzles whenever an object overlaps at least one nozzle of each group said object switches from the transport path defined by said one group of nozzles to the transport path defined by said another group of nozzles;

wherein said means for applying comprises at least one fluidic amplifier means for selectively switching pressurized fluid to and from selective ones of said fluid passages.

6. A Bernoulli conveyor for transporting an endless belt along a predetermined transport path, said conveyor comprismg:

a first member having a transport surface along which said transport path is defined, said first member having a group of nozzles defined therein, the downstream end of each nozzle terminating at said transport surface, the nozzles being disposed relative to one another to define said transport path, each nozzle being angled relative to said transport surface to impart to fluid flowing through that nozzle a flow component directed along said transport path;

a fluid passage arranged deliver pressurized fluid applied thereto to the upstream end of all nozzles in said group of nozzles;

means for applying pressurized fluid to said fluid passage;

whereby said endless belt is supported a short distance from and propelled about said surface by fluid jets issuing from said group of nozzles; and

at least a second group of nozzles defining a second transport path intersecting said first transport path at a determined location on said transport surface, at least one nozzle from each of said first and second transport paths being overlapped by said belt at said predetermined location, said first member being contoured to permit said endless belt to be spaced said short distance from said first member when being transported along each of said transport paths.

7. The combination according to claim 6 wherein said means for applying comprises at least one fluidic amplifier means for selectively switching pressurized fluid to and from selective ones of said fluid passages.

8. A Bernoulli conveyor for transporting an endless belt along a predetermined transport path, said conveyor comprismg:

a first member having a transport surface along which said transport path is defined, said first member having a group of nozzles defined therein, the downstream end of each nozzle terminating at said transport surface, the nozzles being disposed relative to one another to define said transport path, each noule being angled relative to said transport surface to impart to fluid flowing through that nozzle a flow component directed along said transport path;

a fluid passage arranged to deliver pressurized fluid applied thereto to the upstream end of all nozzles in said group of nozzles;

means for applying pressurized fluid to said fluid passage;

whereby said endless belt is supported a short distance from and propelled about said surface by fluid jets issuing from said group of nozzles; and

a second group of nozzles defined in said first member and terminating at said transport surface, each nozzle in said second group being angled to impart to fluid flowing therethrough a flow component directed transversely of the transport direction and along said transport surface, at leave one nozzle of said second group being disposed so as to be overlapped by said endless belt when the latter is being propelled along said transport path.

9. A Bernoulli conveyor for transporting an endless belt along a predetermined transport path, said conveyor comprismg:

a first member having a transport surface along which said transport path is defined, said first member having a group of nozzles defined therein, the downstream end of each nozzle terminating at said transport surface, the nozzles being disposed relative to one another to define said transport path, each nozzle being angled relative to said transport surface to impart to fluid flowing through that nozzle a flow component directed along said transport path;

a fluid passage arranged to deliver pressurized fluid applied thereto to the upstream end of all nonles in said group of nozzles;

means for applying pressurized fluid to said fluid passage;

whereby said endless belt is supported a short distance from and propelled about said surface by fluid jets issuing from said group of nozzles;

a second group of noules defined in said first member and terminating at said transport surface, each nozzle in said second group being angled to impart to fluid flowing therethrough a flow component along said transport surface in the direction of a second transport path defined by said second group of nozzles,

means for selectively applying pressurized fluid to all of said nozzles in said second group;

means for selectively displacing said endless belt from said first transport path to said second transport path comprising a third group of nozzles defined in said first member and angled with respect thereto to impart to fluid flowing through said third group of nozzles a flow component along said transport surface and toward said second transport path, at least one of said nozzles in said second group being disposed to be overlapped by said endless belt when the latter is being transported along said first transport path, and means for selectively applying pressurized fluid to all nozzles in said third group; and

means for selectively displacing said endless belt from said second transport path to said first transport path comprising a fourth group of nozzles defined in said first member angled with respect thereto to impart to fluid flowing through said fourth group of nozzles a flow component along said transport surface and toward said first transport path, at least one nozzle in said fourth group being disposed to be overlapped by said belt when the latter is propelled along said second transport path; and

means for selectively applying pressurized fluid to all nozzles in said fourth group.

10. A Bernoulli conveyor for transporting objects having a relatively flat surface along a predetermined transport path, said conveyor comprising:

a first member having a transport surface along which said transport path is defined, said first member having a group of nozzles defined therein, the downstream end of each nozzle terminating at said transport surface, the nozzles in said group being disposed relative to one another to define said transport path, each nozzle being angled relative to said transport surface to impart to fluid flowing through that nozzle a flow component directed along said transport path,

a second group of noules defined in said first member and terminating at said transport surface, each nozzle in said second group being angled to impart to fluid flowing therethrough a flow component directed transversely of said flow component imparted by said first group of nozzles and along said transport surface, at least one nozzle of said second group being disposed so as to be overlapped by said flat surface of an object being transported when the latter is being propelled along said transport path;

a plurality of fluid passages, one each for each of said groups of nozzles, each passage being arranged to deliver pressurized fluid applied thereto to the upstream end of all the nozzles in a respective group of nozzles;

means for applying pressurized fluid to selective ones of said fluid passages;

whereby said objects are supported a short distance and propelled along said surface by fluid jets issuing from said first group of noules, and whereby upon switching pressurized fluid from said first to said second of said group of nozzles said object is removed from said transport path;

a third group of nozzles defined in said first member and terminating at said transport surface, each nozzle in said third group being angled to impart to fluid flowing therethrough a flow component along said transport surface in the direction of a second transport path defined by said third group of nozzles;

means for selectively applying pressurized fluid to all of said nozzles in said third group;

means for selectively displacing said objects from said first transport path to said second transport path including said second group of nozzles wherein said flow component imparted by said second group of nozzles is directed toward said second transport path;

means for selectively displacing said objects from said second transport path to said first transport path comprising a fourth group of nozzles defined in said first member angled with respect thereto to impart to fluid flowing downstream end of all of said nozzles includes a wall section which tapers into gradual transition with said transport surface, the degree of taper of said wall section being such that a fluid stream issuing from said each nozzle experiences boundary layer attachment to said transport surface. 

1. A Bernoulli conveyor for transporting objects having a relatively flat surface along selectable ones of a plurality of predetermined transport paths, said conveyor comprising: a first member having a transport surface along which said transport paths are defined, said first member having a plurality of groups of nozzles defined therein, the downstream end of each nozzle terminating at said transport surface, the nozzles in each group being disposed relative to one another to define a respective one of said transport paths, each nozzle being angled relative to said transport surface to impart to fluid flowing through that nozzle a flow component directed along the transport path of which that nozzle defines a part, each transport path being sufficiently proximate at least one other transport path at at least one location on said transport surface to permit said relatively flat surface of one of said objects while being transported along said each transport path at said one location to overlap at least one nozzle of said at least one other transport path; a plurality of fluid passages, one each for each of said groups of nozzles, each passage being arranged to deliver pressurized fluid applied thereto to the upstream end of all the nozzles in a respective group of nozzles; and means for applying pressurized fluid to selective ones of said fluid passages; whereby said objects are supported a short distance from and propelled along said surface of fluid jets issuing from whichever group of nozzles has pressurized fluids applied thereto, and whereby upon switching pressurized fluid from one to another of said groups of nozzles whenever an object overlaps at least one nozzle of each group said object switches from the transport path defined by said one group of nozzles to the transport path defined by said another group of nozzles; wherein the object supported a short distance from and transported along said transport surface is an endless conveyor belt surrounding said first member.
 2. The combination according to claim 1 wherein at least two of said transport paths intersect at said one location on said transport surface, said first member being contoured to permit said endless belt to be spaced said short distance from said first member when being transported along each of said transport paths.
 3. The combination according to claim 2 further comprising a second member disposed beneath said first member for preventing said endless belt from sagging while passing beneath said first member, said second member including a support surface disposed proximate the underside of said first member to permit said endless belt to pass between said support surface and the underside of said first member, said second member including means for issuing pressurized fluid from said support surface against said endless belt to cause said endless belt to move parallel to said support surface while under said first member.
 4. The combination according to claim 3 wherein said means for issuing includes a second plurality of nozzles terminating at said support surface and angled to impart to flow therethrough a flow component in the transport direction of said endless belt at the underside of said first member, and means for supplying pressurized fluid to said second plurality of nozzles.
 5. A Bernoulli conveyor for transporting objects having a relatively flat surface along selectable ones of a plurality of predetermined transport paths, said conveyor comprising: a first member having a transport surface along which said transport paths are defined, said first member having a plurality of groups of nozzles defined therein, the downstream end of each nozzle terminating at said transport surface, the nozzles in each group being disposed relative to one another to define a respective one of said transport paths, each nozzle being angled relative to said transport surface to impart to fluid flowing through that nozzle a flow component directed along the transport path of which that nozzle defines a part, each transport path being sufficiently proximate at least one other transport path at at least one location on said transport surface to permit said relatively flat surface of one of said objects while being transported along said each transport path at said one location to overlap at least one nozzle of said at least one other transport path; a plurality of fluid passages, one each for each of said groups of nozzles, each passage being arranged to deliver pressurized fluid applied thereto to the upstream end of all the nozzles in a respective group of nozzles; and means for applying pressurized fluid to selective ones of said fluid passages; whereby said objects are supported a short distance from and propelled along said surface by fluid jets issuing from whichever group of nozzles has pressurized fluid applied thereto, and whereby upon switching pressurized fluid from one to another of said groups of nozzles whenever an object overlaps at least one nozzle of each group said object switches from the transport path defined by said one group of nozzles to the transport path defined by said another group of nozzles; wherein said means for applying comprises at least one fluidic amplifier means for selectively switching pressurized fluid to and from selective ones of said fluid passages.
 6. A Bernoulli conveyor for transporting an endless belt along a predetermined transport path, said conveyor comprising: a first member having a transport surface along which said transport path is defined, said first member having a group of nozzles defined therein, the downstream end of each nozzle terminating at said transport surface, the nozzles being disposed relative to one another to define said transport path, each nozzle being angled relative to said transport surface to impart to fluid flowing through that nozzle a flow component directed along said transport path; a fluid passage arranged deliver pressurized fluid applied thereto to the upstream end of all nozzles in said group of nozzles; means for applying pressurized fluid to said fluid passage; whereby said endless belt is supported a short distance from and propelled about said surface by fluid jets issuing from said group of nozzles; and at least a second group of nozzles defining a second transport path intersecting said first transport path at a determined location on said transport surface, at least one nozzle from each of said first and second transport paths being overlapped by said belt at said predetermined location, said first member being contoured to permit said endless belt to be spaced said short distance from said first member when being transported along each of said transport paths.
 7. The combination according to claim 6 wherein said means for applying comprises at least one fluidic amplifier means for selectively switching pressurized fluid to and from selective ones of said fluid passages.
 8. A Bernoulli conveyor for transporting an endless belt along a predetermined transport path, said conveyor comprising: a first member having a transport surface along which said transport path is defined, said first member having a group of nozzles defined therein, the downstream end of each nozzle terminating at said transport surface, the nozzles being disposed relative to one another to define said transport path, each nozzle being angled relative to said transport surface to impart to fluid flowing through that nozzle a flow component directed along said transport path; a fluid passage arranged to deliver pressurized fluid applied thereto to the upstream end of all nozzles in said group of nozzles; means for applying pressurized fluid to said fluid passage; whereby said endless belt is supported a short distance from and propelled about said surface by fluid jets issuing from said group of nozzles; and a second group of nozzles defined in said first member and terminating at said transport surface, each nozzle in said second group being angled to impart to fluid flowing therethrough a flow component directed transversely of the transport direction and along said transport surface, at leave one nozzle of said second group being disposed so as to be overlapped by said endless belt when the latter is being propelled along said transport path.
 9. A Bernoulli conveyor for transporting an endless belt along a predetermined transport path, said conveyor comprising: a first member having a transport surface along which said transport path is defined, said first member having a group of nozzles defined therein, the downstream end of each nozzle terminating at said transport surface, the nozzles being disposed relative to one another to define said transport path, each nozzle being angled relative to said transport surface to impart to fluid flowing through that nozzle a flow component directed along said transport path; a fluid passage arranged to deliver pressurized fluid applied thereto to the upstream end of all nozzles in said group of nozzles; means for applying pressurized fluid to said fluid passage; whereby said endless belt is supported a short distance from and propelled about said surface by fluid jets issuing from said group of nozzles; a second group of nozzles defined in said first member and terminating at said transport surface, each nozzle in said second group being angled to impart to fluid flowing therethrough a flow component along said transport surface in the direction of a second transport path defined by said second group of nozzles, means for selectively applying pressurized fluid to all of said nozzles in said second group; means for selectively displacing said endless belt from said first transport path to said second transport path comprising a third group of nozzles defined in said first member and angled with respect thereto to impart to fluid flowing through said third group of nozzles a flow component along said transport surface and toward said second transport path, at least one of saId nozzles in said second group being disposed to be overlapped by said endless belt when the latter is being transported along said first transport path, and means for selectively applying pressurized fluid to all nozzles in said third group; and means for selectively displacing said endless belt from said second transport path to said first transport path comprising a fourth group of nozzles defined in said first member angled with respect thereto to impart to fluid flowing through said fourth group of nozzles a flow component along said transport surface and toward said first transport path, at least one nozzle in said fourth group being disposed to be overlapped by said belt when the latter is propelled along said second transport path; and means for selectively applying pressurized fluid to all nozzles in said fourth group.
 10. A Bernoulli conveyor for transporting objects having a relatively flat surface along a predetermined transport path, said conveyor comprising: a first member having a transport surface along which said transport path is defined, said first member having a group of nozzles defined therein, the downstream end of each nozzle terminating at said transport surface, the nozzles in said group being disposed relative to one another to define said transport path, each nozzle being angled relative to said transport surface to impart to fluid flowing through that nozzle a flow component directed along said transport path, a second group of nozzles defined in said first member and terminating at said transport surface, each nozzle in said second group being angled to impart to fluid flowing therethrough a flow component directed transversely of said flow component imparted by said first group of nozzles and along said transport surface, at least one nozzle of said second group being disposed so as to be overlapped by said flat surface of an object being transported when the latter is being propelled along said transport path; a plurality of fluid passages, one each for each of said groups of nozzles, each passage being arranged to deliver pressurized fluid applied thereto to the upstream end of all the nozzles in a respective group of nozzles; means for applying pressurized fluid to selective ones of said fluid passages; whereby said objects are supported a short distance and propelled along said surface by fluid jets issuing from said first group of nozzles, and whereby upon switching pressurized fluid from said first to said second of said group of nozzles said object is removed from said transport path; a third group of nozzles defined in said first member and terminating at said transport surface, each nozzle in said third group being angled to impart to fluid flowing therethrough a flow component along said transport surface in the direction of a second transport path defined by said third group of nozzles; means for selectively applying pressurized fluid to all of said nozzles in said third group; means for selectively displacing said objects from said first transport path to said second transport path including said second group of nozzles wherein said flow component imparted by said second group of nozzles is directed toward said second transport path; means for selectively displacing said objects from said second transport path to said first transport path comprising a fourth group of nozzles defined in said first member angled with respect thereto to impart to fluid flowing through said fourth group of nozzles a flow component along said transport surface and toward said first transport path, at least one nozzle in said fourth group being disposed to be overlapped by said objects when the latter are propelled along said second transport path, and means for selectively applying pressurized fluid to all nozzles in said fourth group.
 11. The combination according to claim 10 wherein the downstream end of all of said nozzles includes a wall section which tapers into gradual transition With said transport surface, the degree of taper of said wall section being such that a fluid stream issuing from said each nozzle experiences boundary layer attachment to said transport surface. 